Reframing NCDs and Global Health: Thoughts on the Lancet Debate

In light of this week’s upcoming UN High Level meeting on non-communicable diseases (NCDs), it may be useful to revisit last year’s Lancet Global Health discussion on reframing NCDs (Allen, 2017; Allen & Feigl, 2017c; Horton, 2017). The debate highlighted a number of issues in typology and framing in global health, some of which were discussed in the Chronic Disease in Sub-Saharan Africa project’s recent conference “Africa and the Epidemiological Imagination” at the Institute of Advanced Studies, University College London. One issue raised is the complications that arise from the desire to simplify the world by classifying objects, phenomena and characteristics into discrete categories—a prime example being the problematic construction of racial categories. In the health field, this also comes up when determining how to pathologise humans and human conditions: When does a blood pressure become hypertensive as opposed to normotensive? When does a body mass index become overweight? When does a blood sugar level become diabetic? When do certain behaviours become mental illness?

Allen and Feigl (2017b) eventually proposed the phrase ‘socially-transmitted conditions (STCs)’ as an alternative to the classification NCDs in order to draw attention to the shared commercial and social determinants of these conditions. I liked the idea; however, like Cavalin and Lescoat (2017), I worried that this phrase could inadvertently lead to the suggestion that infectious diseases do not share some of these social determinants. The authors did note that all diseases are influenced by social factors but maybe underestimated the extent to which this is the case. For example, one could argue that the severity of the HIV/AIDS and TB syndemic in southern Africa was largely facilitated by the migrant labour economic system of the mining industries, a system which developed in colonial times and persists to this day. The social gradients we observe in nutritional deficiencies, diarrhoeal diseases and maternal mortality are also linked to political economies and inequalities at local and global levels that allow some people and populations to remain impoverished. One could therefore say that all ‘communicable’ or ‘infectious’ diseases are socially transmitted and preventable. Likewise, many infectious disease epidemics throughout history have also been driven by processes such as urbanisation, industrialisation, poverty and structural inequality. So, distinguishing NCDs from infectious diseases in terms of social transmission may not entirely solve the naming problem, though I think the motivation behind the suggestion was laudable.

The challenge with NCDs is that as a category, they encompass so many conditions with differing causes and aetiologies—essentially everything that is not an infection (in the traditional sense); not maternal, neonatal or nutritional (again, in the traditional sense); and in some cases (though this is debated) not an injury. An alternative strategy may be to keep smaller groupings, related to the aetiology of disease, similar to that used for infectious diseases: (i.e., genetic diseases, mental illnesses, autoimmune disorders, etc.)

In the case of what many people mean by the narrow definition of ‘NCDs,’ namely the ‘big four’ disease categories (cancer, cardiovascular disease, diabetes, chronic respiratory diseases) that often share common risk factors, perhaps some reference to inflammatory processes may help to define them? From a merely proximal biological standpoint, all four of these classes of disease categories (as well as other conditions such as autoimmune disorders) have been linked to a chronic inflammatory response. This inflammation may initially be triggered by exposure to infectious agents (human papillomavirus, strep, hepatitis C), environmental toxins and chemicals (air pollution, tobacco smoke, asbestos, alcohol), injury (physical injury or radiation), psychosocial exposures (stress) and biological processes (metabolic factors, etc.) (Chen et al., 2018; Hunter, 2012). So perhaps, such conditions could be viewed as ‘diseases of chronic inflammation’ in terms of their aetiology. [Chronic inflammatory diseases is a term that is already in use but often to describe a more limited set of conditions relating to autoimmunity (Straub & Schradin, 2016).]

Of course, this does not solve the problem of mobilizing action and focusing attention on the structural determinants of these conditions that Allen and Feigl (2017b) raised. Nor does it help to unite forces across disease groups. Cavalin and Lescoat (2017) argued that referring to ‘NCDs’ as ‘STCs’ might not result in more action, given that in theory, NCDs were already seen as having social, behavioural and environmental causes; yet that did not stop epidemiology from maintaining a biomedical focus. Allen and Feigl responded that addressing social drivers of NCDs is a good starting point that could lead to upstream thinking in other areas (Allen & Feigl, 2017a). Nevertheless, I would also add that upstream thinking when it comes to disease is not necessarily new and has been the focus of fields like social epidemiology and other social sciences, though translating this view into political action is always tricky. Some social epidemiologists don’t go beyond the social determinants of health at the individual level, but others do focus on the upstream societal and socio-political determinants of health (Krieger, 2011). From this perspective, all disease has social causes or implications. However, even before the birth of social epidemiology as a field in the mid- to late-twentieth century, the history of epidemiological inquiry had an upstream focus. Louis-Rene Villermé, Rudolf Virchow, Friedrich Engels, Edwin Chadwick and others examined morbidity and mortality (largely due to infectious and environmental causes) among the urban and industrial poor in Europe in the 1800s. They related ill health to issues of class, political economy, industrialisation, and the social and environmental conditions in which many people were forced to live and work. Disease was therefore societally-produced (Krieger, 2011).

About Kafui Adjaye-Gbewonyo

Kafui is a Research Associate with the Chronic Disease in Sub-Saharan Africa team. She is examining recent trends in chronic diseases and potential social, demographic, behavioural, psychosocial and environmental explanations for these trends using data from South African and Ghanaian population surveys. She is also collecting family health histories of chronic disease through interviews with coastal Ghanaians.

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Chronic Disease in Sub-Saharan Africa

A critical history of an ‘epidemiological transition’

The project seeks to critically evaluate the history of what is viewed as an ‘epidemic’ of chronic and non-communicable diseases in sub-Saharan Africa and provide an historical account of the evolution of chronic and non-communicable diseases in Africa, going beyond a simple account of ‘transition’, and to contribute to wider debates on the nature of epidemiological change.